x86/microcode: Remove unused struct cpu_info_ctx

This looks unused since

  2071c0ae ("x86/microcode: Simplify init path even more")

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240506004300.770564-1-linux@treblig.org